Download Earthquakes * Day 1 - NVHSEarthScienceOlsen

Earthquakes – Day 1
October 11, 2010
Objectives
• I will be able to describe an earthquake’s
_________such as epicenter, focus,
magnitude, and intensity
• I will be able to analyze the ____________of
seismic earthquake waves
• I will be able to determine earthquake
____________from a travel-time __________
Key Points
• To describe the location of earthquakes, we use the
terms focus and epicenter
• When analyzing how earthquakes travel, we talk about
the 3 main types of earthquake waves: s, p, and surface
– These waves travel at different speeds and cause differing
amounts of destruction
– The magnitude of an earthquake measures the amplitude
of the largest wave
• Major earthquakes can be preceded by foreshocks and
followed by aftershocks
• The intensity of an earthquake describes the amount of
shaking at a specific location
What are Earthquakes?
• Earthquake video
• Take note of at least 4 facts
1.
2.
3.
4.
______________________
______________________
______________________
______________________
Cause of Earthquakes
• What causes earthquakes to occur?
• Where do we usually find earthquakes
occurring?
Cause of Earthquakes
• Earthquakes are the __________or _______of
the Earth produced by the rapid release of _____
• When rocks are subjected to large forces, such as
those associated with plate movement, the rocks
are __________and _______________
• When rocks cannot withstand the stress any
longer, they __________and energy is _________
• ________are fractures in the earth where
movement has occurred
• ______________ __________ ___________
Earthquake features
1. Location
– _____: the place where the earthquake starts_________________
• Energy radiates out in _____________
– __________: the location on the surface of earth
directly __________________
Earthquake features
2. _____________: smaller earthquakes that _______or
__________________major earthquakes
3. ____________: smaller earthquakes that occur
____________ major earthquakes
4. _____________: the amount of shaking produced by
an earthquake at a given location
5. _____________: the “______” of the earthquake
- Richter magnitude: determined from the _________
(height) of the largest seismic wave
- Moment magnitude: determined from the
displacement (movement) of the fault zone
Earthquake Waves
• All of the above features are a result of the
earthquake _________that transport the
___________from the ______outward in ____
____________________
• ______ general categories
– _________________: travel along Earth’s surface
– _______________: travel from the focus
__________Earth’s ____________
Earthquake Waves
• Surface waves
– Travel along Earth’s ___________layer
– Their motion is _____________
• Like waves move a ship on the ocean
• Up/down and side-to-side motion
– The ________________type of earthquake wave
• Because they travel along the ground they cause
______________resting on the land to __________
Earthquake Waves
• Body waves- 2 types
1. P-waves
• __________waves- they arrive _______
• Travel the _____________
• Classified as “compressional waves”_____________________________
• Can travel through __________,
___________, and _____________
Earthquake Waves
• Body waves
2. S-waves
• _______________________waves- they
arrive ___________P-waves
• Travel more __________than P-waves
• Travel at right angles to the direction
they move
• Travel through _________________
Check In – Answer the following on a
SEPARATE piece of paper in COMPLETE
sentences:
1. What is the epicenter of an earthquake?
2. What is the source of an earthquake called?
3. What are the smaller earthquakes that precede
major earthquakes called?
4. Which type of seismic wave travels the fastest?
5. Which type of seismic wave travels the slowest?
6. Which type of seismic wave causes the most
destruction?
Locating Earthquakes- Part I
• Because P-waves and S-waves travel
at ________________we can use the
_________ in their ___________at a
given location to figure out the
distance to the earthquake’s
______________________
• This information is presented in a
__________________________
Reading Travel-time graphs
A. ________________for the
arrival of the waves
B. ___________from the
recording station to the
_____________________
-____________at the top
-_________at the bottom